1
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Sias C, Subramanian N, Hodnett G, Rooney W, Bagavathiannan M. Rate of crop‐weed hybridization in
Sorghum bicolor
×
Sorghum halepense
is influenced by genetic background, pollen load, and the environment. Evol Appl 2023; 16:781-796. [PMID: 37124087 PMCID: PMC10130556 DOI: 10.1111/eva.13536] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 12/22/2022] [Accepted: 02/02/2023] [Indexed: 03/29/2023] Open
Abstract
The potential for gene flow between cultivated species and their weedy relatives poses agronomic and environmental concerns, particularly when there are opportunities for the transfer of adaptive or agronomic traits such as herbicide resistance into the weedy forms. Grain sorghum (Sorghum bicolor) is an important crop capable of interspecific hybridization with its weedy relative johnsongrass (Sorghum halepense). Previous findings have shown that triploid progenies resulting from S. bicolor × S. halepense crosses typically collapse with only a few developing into mature seeds, whereas tetraploids often fully develop. The objective of this experiment was to determine the impact of S. bicolor genotype and pollen competition on the frequency of hybridization between S. bicolor and S. halepense. A total of 12 different cytoplasmic male sterile S. bicolor genotypes were compared with their respective male fertile lines across 2 years, to assess the frequency of hybridization and seed set when S. halepense served as the pollinator parent. Results indicate significant differences in the frequency of interspecific hybridization among the S. bicolor genotypes, and pollen fertility in S. bicolor reduced the rate of this interspecific hybridization by up to two orders of magnitude. Further, hybridization rates greatly varied across the two study environments. Results are helpful for developing appropriate gene flow mitigation strategies and indicate that gene flow could be reduced by the selection of appropriate seed parents for sorghum hybrids.
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Affiliation(s)
- Cynthia Sias
- Department of Soil and Crop SciencesTexas A&M UniversityCollege StationTexasUSA
| | - Nithya Subramanian
- Department of Soil and Crop SciencesTexas A&M UniversityCollege StationTexasUSA
| | - George Hodnett
- Department of Soil and Crop SciencesTexas A&M UniversityCollege StationTexasUSA
| | - William Rooney
- Department of Soil and Crop SciencesTexas A&M UniversityCollege StationTexasUSA
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Sohn SI, Thamilarasan SK, Pandian S, Oh YJ, Kang HJ, Shin EK. Characteristics and Fitness Analysis through Interspecific Hybrid Progenies of Transgenic Brassica napus and B. rapa L. ssp. Int J Mol Sci 2022; 23:ijms231810512. [PMID: 36142426 PMCID: PMC9506035 DOI: 10.3390/ijms231810512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/01/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
Interspecific hybridization between transgenic crops and their wild relatives is a major concern for transgene dispersal in the environment. Under controlled conditions, artificial hand pollination experiments were performed in order to assess the hybridization potential and the fitness of interspecific hybrids between Brassica rapa and genetically modified (GM) Brassica napus. Initially, six subspecies of B. rapa were hybridized with GM B. napus through hand pollination. In the resulting F1 hybrids, the combination of B. rapa ssp. narinosa (♀) × GM B. napus (♂) had the highest crossability index (16.9 ± 2.6). However, the F1 selfing progenies of B. rapa ssp. rapa (♀) × GM B. napus were found to be more effective in producing viable future generations with the highest crossability index (1.6 ± 0.69) compared to other subspecies. Consequently, they were used for the generation of F2 and F3 progenies. The 18 different morphological characteristics among the parental cross-combinations and F1 hybrid progenies were measured and visualized through hierarchical clustering. Different generations were found to be grouped based on their different morphological characteristics. The chromosome numbers among the interspecific hybrids ranged from 2n = 29 to 2n = 40. Furthermore, the SSR markers revealed the presence of genomic portions in the hybrids in comparison with their parental lines. There is a high possibility of transgene flow between GM B. napus and B. rapa. The study concluded that the interspecific hybrids between B. napus and B. rapa can be viable and can actively hybridize up to F3 generations and more. This suggests that the GM B. napus can disperse the transgene into B. rapa, and that it can pass through for several generations by hand pollination in a greenhouse environment.
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Affiliation(s)
- Soo-In Sohn
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju 54874, Korea
- Correspondence: ; Tel.: +82-063-238-4712
| | - Senthil Kumar Thamilarasan
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju 54874, Korea
| | - Subramani Pandian
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju 54874, Korea
| | - Young-Ju Oh
- Institute for Future Environment Ecology Co., Ltd., Jeonju 54883, Korea
| | - Hyeon-Jung Kang
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju 54874, Korea
| | - Eun-Kyoung Shin
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju 54874, Korea
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Bayer PE, Scheben A, Golicz AA, Yuan Y, Faure S, Lee H, Chawla HS, Anderson R, Bancroft I, Raman H, Lim YP, Robbens S, Jiang L, Liu S, Barker MS, Schranz ME, Wang X, King GJ, Pires JC, Chalhoub B, Snowdon RJ, Batley J, Edwards D. Modelling of gene loss propensity in the pangenomes of three Brassica species suggests different mechanisms between polyploids and diploids. Plant Biotechnol J 2021; 19:2488-2500. [PMID: 34310022 PMCID: PMC8633514 DOI: 10.1111/pbi.13674] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 07/11/2021] [Accepted: 07/20/2021] [Indexed: 05/26/2023]
Abstract
Plant genomes demonstrate significant presence/absence variation (PAV) within a species; however, the factors that lead to this variation have not been studied systematically in Brassica across diploids and polyploids. Here, we developed pangenomes of polyploid Brassica napus and its two diploid progenitor genomes B. rapa and B. oleracea to infer how PAV may differ between diploids and polyploids. Modelling of gene loss suggests that loss propensity is primarily associated with transposable elements in the diploids while in B. napus, gene loss propensity is associated with homoeologous recombination. We use these results to gain insights into the different causes of gene loss, both in diploids and following polyploidization, and pave the way for the application of machine learning methods to understanding the underlying biological and physical causes of gene presence/absence.
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Affiliation(s)
- Philipp E. Bayer
- School of Biological Sciences and the Institute of AgricultureFaculty of ScienceThe University of Western AustraliaCrawleyWAAustralia
| | - Armin Scheben
- School of Biological Sciences and the Institute of AgricultureFaculty of ScienceThe University of Western AustraliaCrawleyWAAustralia
| | - Agnieszka A. Golicz
- Plant Molecular Biology and Biotechnology LaboratoryFaculty of Veterinary and Agricultural SciencesUniversity of MelbourneParkvilleVICAustralia
| | - Yuxuan Yuan
- School of Biological Sciences and the Institute of AgricultureFaculty of ScienceThe University of Western AustraliaCrawleyWAAustralia
| | | | - HueyTyng Lee
- Department of Plant BreedingIFZ Research Centre for BiosystemsLand Use and NutritionJustus Liebig University GiessenGiessenGermany
| | - Harmeet Singh Chawla
- Department of Plant BreedingIFZ Research Centre for BiosystemsLand Use and NutritionJustus Liebig University GiessenGiessenGermany
| | - Robyn Anderson
- School of Biological Sciences and the Institute of AgricultureFaculty of ScienceThe University of Western AustraliaCrawleyWAAustralia
| | | | - Harsh Raman
- NSW Department of Primary IndustriesWagga Wagga Agricultural Institute, PMBWagga WaggaNSWAustralia
| | - Yong Pyo Lim
- Department of HorticultureChungnam National UniversityDaejeonSouth Korea
| | | | - Lixi Jiang
- Institute of crop scienceDepartment of Agronomy and Plant BreedingZhejiang UniversityHangzhouChina
| | - Shengyi Liu
- Chinese Academy of Agricultural SciencesOil Crops Research InstituteWuhanChina
| | - Michael S. Barker
- Department of Ecology & Evolutionary BiologyUniversity of ArizonaTucsonAZUSA
| | - M. Eric Schranz
- Biosystematics GroupWageningen University and Research CenterWageningenThe Netherlands
| | - Xiaowu Wang
- Institute of Vegetables and FlowersChinese Academy of Agricultural Sciences (IVF, CAAS)BeijingChina
| | - Graham J. King
- Southern Cross Plant ScienceSouthern Cross UniversityLismoreNSWAustralia
| | - J. Chris Pires
- Division of Biological SciencesBond Life Sciences CenterUniversity of MissouriColumbiaMissouriUSA
| | - Boulos Chalhoub
- Institute of crop scienceDepartment of Agronomy and Plant BreedingZhejiang UniversityHangzhouChina
| | - Rod J. Snowdon
- Department of Plant BreedingIFZ Research Centre for BiosystemsLand Use and NutritionJustus Liebig University GiessenGiessenGermany
| | - Jacqueline Batley
- School of Biological Sciences and the Institute of AgricultureFaculty of ScienceThe University of Western AustraliaCrawleyWAAustralia
| | - David Edwards
- School of Biological Sciences and the Institute of AgricultureFaculty of ScienceThe University of Western AustraliaCrawleyWAAustralia
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Song X, Yan J, Zhang Y, Li H, Zheng A, Zhang Q, Wang J, Bian Q, Shao Z, Wang Y, Qiang S. Gene Flow Risks From Transgenic Herbicide-Tolerant Crops to Their Wild Relatives Can Be Mitigated by Utilizing Alien Chromosomes. Front Plant Sci 2021; 12:670209. [PMID: 34177986 PMCID: PMC8231706 DOI: 10.3389/fpls.2021.670209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/14/2021] [Indexed: 06/13/2023]
Abstract
Integration of a transgene into chromosomes of the C-genomes of oilseed rape (AACC, 2n = 38) may affect their gene flow to wild relatives, particularly Brassica juncea (AABB, 2n = 36). However, no empiric evidence exists in favor of the C-genome as a safer candidate for transformation. In the presence of herbicide selections, the first- to fourth-generation progenies of a B. juncea × glyphosate-tolerant oilseed rape cross [EPSPS gene insertion in the A-genome (Roundup Ready, event RT73)] showed more fitness than a B. juncea × glufosinate-tolerant oilseed rape cross [PAT gene insertion in the C-genome (Liberty Link, event HCN28)]. Karyotyping and fluorescence in situ hybridization-bacterial artificial chromosome (BAC-FISH) analyses showed that crossed progenies from the cultivars with transgenes located on either A- or C- chromosome were mixoploids, and their genomes converged over four generations to 2n = 36 (AABB) and 2n = 37 (AABB + C), respectively. Chromosome pairing of pollen mother cells was more irregular in the progenies from cultivar whose transgene located on C- than on A-chromosome, and the latter lost their C-genome-specific markers faster. Thus, transgene insertion into the different genomes of B. napus affects introgression under herbicide selection. This suggests that gene flow from transgenic crops to wild relatives could be mitigated by breeding transgenic allopolyploid crops, where the transgene is inserted into an alien chromosome.
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Liu JY, Sheng ZW, Hu YQ, Liu Q, Qiang S, Song XL, Liu B. Fitness of F1 hybrids between 10 maternal wild soybean populations and transgenic soybean. Transgenic Res 2021; 30:105-119. [PMID: 33400167 PMCID: PMC7854435 DOI: 10.1007/s11248-020-00230-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/08/2020] [Indexed: 11/05/2022]
Abstract
The releasing of transgenic soybeans (Glycine max (L.) Merr.) into farming systems raises concerns that transgenes might escape from the soybeans via pollen into their endemic wild relatives, the wild soybean (Glycine soja Sieb. et Zucc.). The fitness of F1 hybrids obtained from 10 wild soybean populations collected from China and transgenic glyphosate-resistant soybean was measured without weed competition, as well as one JLBC-1 F1 hybrid under weed competition. All crossed seeds emerged at a lower rate from 13.33-63.33%. Compared with those of their wild progenitors, most F1 hybrids were shorter, smaller, and with decreased aboveground dry biomass, pod number, and 100-seed weight. All F1 hybrids had lower pollen viability and filled seeds per plant. Finally, the composite fitness of nine F1 hybrids was significantly lower. One exceptional F1 hybrid was IMBT F1, in which the composite fitness was 1.28, which was similar to that of its wild progenitor due to the similarities in pod number, increased aboveground dry biomass, and 100-seed weight. Under weed competition, plant height, aboveground dry biomass, pod number per plant, filled seed number per plant, and 100-seed weight of JLBC-1 F1 were lower than those of the wild progenitor JLBC-1. JLBC-1 F1 hybrids produced 60 filled seeds per plant. Therefore, F1 hybrids could emerge and produce offspring. Thus, effective measures should be taken to prevent gene flow from transgenic soybean to wild soybean to avoid the production F1 hybrids when releasing transgenic soybean in fields in the future.
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Affiliation(s)
- Jin Yue Liu
- Weed Research Laboratory, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Ze Wen Sheng
- Weed Research Laboratory, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Yu Qi Hu
- Weed Research Laboratory, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Qi Liu
- Weed Research Laboratory, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Sheng Qiang
- Weed Research Laboratory, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Xiao Ling Song
- Weed Research Laboratory, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China.
| | - Biao Liu
- Weed Research Laboratory, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
- Ministry of Ecology and Environment, Nanjing Institute of Environmental Sciences, Nanjing, 210042, People's Republic of China
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Torres Carbonell F, Ureta S, Pandolfo C, Presotto A. Molecular characterization of imidazolinone-resistant Brassica rapa × B. napus hybrids. Environ Monit Assess 2020; 192:746. [PMID: 33145668 DOI: 10.1007/s10661-020-08711-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 10/26/2020] [Indexed: 06/11/2023]
Abstract
Herbicide-resistant oilseed rape (Brassica napus) cultivation in our country entails the risk of gene transfer to related wild species. One of these species is the wild turnip (B. rapa), an important weed of winter crops widely distributed in the Pampas region. Despite hybridization risks, Clearfield ® oilseed rape is available in Argentina. In 2008, a B. rapa population, which was sympatric to an imidazolinone-resistant and a conventional oilseed rape cultivar, was located on a farm in the main cropping area of the country. Herbicide-resistant individuals were found in the progeny of this population in a herbicide screening test. Therefore, a molecular characterization using cleaved amplified polymorphic sequence (CAPS) and simple sequence repeat (SSR) markers was conducted on these plants to determine their hybrid nature and to establish the origin of the imidazolinone resistance trait. The results of this study, along with information of field records, confirmed that the resistant plants were first generation interspecific hybrids. Imidazolinone resistance had been effectively transferred from the herbicide-resistant oilseed rape, even in the particular situation of pollen competition. Oilseed rape resistant cultivars are becoming more common in the country. So, considering that seed loss and crop volunteers are common in these species, it is crucial to avoid the dispersion of new resistant weed biotypes as they reduce the effectiveness of chemical control technologies.
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Affiliation(s)
- Francisco Torres Carbonell
- Dpto. Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina.
| | - Soledad Ureta
- Dpto. Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina
| | - Claudio Pandolfo
- Dpto. Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina
- CERZOS, Universidad Nacional del Sur (UNS)-CONICET, Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | - Alejandro Presotto
- Dpto. Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina
- CERZOS, Universidad Nacional del Sur (UNS)-CONICET, Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
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7
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Yoshida T, Kawanabe T, Bo Y, Fujimoto R, Kawabe A. Genome-Wide Analysis of Parent-of-Origin Allelic Expression in Endosperms of Brassicaceae Species, Brassica rapa. Plant Cell Physiol 2018; 59:2590-2601. [PMID: 30165552 DOI: 10.1093/pcp/pcy178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/24/2018] [Indexed: 05/06/2023]
Abstract
Uniparental gene expression, observed in both animals and plants, is termed genomic imprinting. Genomic imprinting is a well-known epigenetic phenomenon regulated through epigenetic modifications such as DNA methylation and histone modifications. Recent genome-wide studies of endosperm transcription have revealed the rapid change of imprinted genes between species, suggesting the flexibility of this phenomenon. Although the functional significance and evolutionary trends of imprinted genes are still obscure, it can be clarified by inter-species comparisons. In this study, we analyzed the pattern of genomic imprinting in Brassica rapa, a species related to Arabidopsis thaliana. Compared with the ancient karyotype of A. thaliana and B. rapa, B. rapa has a triplicated genome. Many imprinted genes, beyond the estimated number previously reported in other species, were observed. Several imprinted genes have been conserved among species in Brassicaceae. We also observed rapid molecular evolution of imprinted genes compared to non-imprinted genes in B. rapa. Especially, imprinted gene overlapping between species showed more rapid molecular evolution and preferential expression in endosperms. It may imply that a small number of imprinted genes have retained functional roles among diverged species and have been the target of natural selection.
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Affiliation(s)
| | - Takahiro Kawanabe
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Yina Bo
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Akira Kawabe
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
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Baaij BM, Kim HK, Grosser K, Worrich A, de Jong TJ. Slug herbivory on hybrids of the crop Brassica napus and its wild relative B. rapa. Basic Appl Ecol 2018; 31:52-60. [DOI: 10.1016/j.baae.2018.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Mikhaylova EV, Kuluev BR. Potential for gene flow from genetically modified Brassica napus on the territory of Russia. Environ Monit Assess 2018; 190:557. [PMID: 30159768 DOI: 10.1007/s10661-018-6946-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 08/22/2018] [Indexed: 06/08/2023]
Abstract
Gene flow from genetically modified crops has been studied for more than 20 years, but public concern still remains. A lot of data on this matter is obtained on the territory of EU and the USA, but in the majority of countries, such experiments were never carried out. Here, we present the first study of interspecific and intraspecific hybridization of transgenic Brassica napus on the territory of Russia. The experiment was conducted using two different models of coexistence. Cross-pollination with related species was more frequent in mixed than that in separated populations. We observed maximum 4.1% of transgenic seeds in the progeny of Brassica rapa and 0.6% in the progeny of Brassica juncea. The highest intraspecific hybridization rate of 0.67% was observed in separated populations. DNA fragments, typical to both parents, were present in the genome of the hybrids. The risk of gene flow in Russia is relatively low, but it will be problematic to do environmental monitoring on such a big territory. However, instead of banning the cultivation of genetically modified crops, some new varieties with visually detectable selective traits could be designed and approved for cultivation.
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Affiliation(s)
- Elena V Mikhaylova
- Laboratory of Bioengineering of plants and microorganisms, Institute of Biochemistry and Genetics UFRC RAS, Prospekt Oktabrya, 71, Ufa, Russian Federation, 450054.
| | - Bulat R Kuluev
- Laboratory of Bioengineering of plants and microorganisms, Institute of Biochemistry and Genetics UFRC RAS, Prospekt Oktabrya, 71, Ufa, Russian Federation, 450054
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Pandolfo CE, Presotto A, Carbonell FT, Ureta S, Poverene M, Cantamutto M. Transgene escape and persistence in an agroecosystem: the case of glyphosate-resistant Brassica rapa L. in central Argentina. Environ Sci Pollut Res Int 2018; 25:6251-6264. [PMID: 29243152 DOI: 10.1007/s11356-017-0726-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 11/08/2017] [Indexed: 05/25/2023]
Abstract
Brassica rapa L. is an annual Brassicaceae species cultivated for oil and food production, whose wild form is a weed of crops worldwide. In temperate regions of South America and especially in the Argentine Pampas region, this species is widely distributed. During 2014, wild B. rapa populations that escaped control with glyphosate applications by farmers were found in this area. These plants were characterized by morphology and seed acidic profile, and all the characters agreed with B. rapa description. The dose-response assays showed that the biotypes were highly resistant to glyphosate. It was also shown that they had multiple resistance to AHAS-inhibiting herbicides. The transgenic origin of the glyphosate resistance in B. rapa biotypes was verified by an immunological test which confirmed the presence of the CP4 EPSPS protein and by an event-specific GT73 molecular marker. The persistence of the transgene in nature was confirmed for at least 4 years, in ruderal and agrestal habitats. This finding suggests that glyphosate resistance might come from GM oilseed rape crops illegally cultivated in the country or as a seed contaminant, and it implies gene flow and introgression between feral populations of GM B. napus and wild B. rapa. The persistence and spread of the resistance in agricultural environments was promoted by the high selection pressure imposed by intensive herbicide usage in the prevalent no-till farming systems.
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Affiliation(s)
- Claudio E Pandolfo
- Dpto. Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Argentina.
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-CONICET, Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina.
| | - Alejandro Presotto
- Dpto. Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Argentina
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-CONICET, Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | | | - Soledad Ureta
- Dpto. Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Argentina
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-CONICET, Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | - Mónica Poverene
- Dpto. Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Argentina
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-CONICET, Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | - Miguel Cantamutto
- Dpto. Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi, Ruta 3 Km 794, 8142, Hilario Ascasubi, Villarino, Argentina
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de Jong TJ, Escobedo Quevedo K, van der Veen-van Wijk CAM, Moshgani M. Performance of aneuploid backcross hybrids between the crop Brassica napus and its wild relative B. rapa. Plant Biol (Stuttg) 2018; 20:67-74. [PMID: 28921773 DOI: 10.1111/plb.12629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 09/13/2017] [Indexed: 06/07/2023]
Abstract
Crossings between the diploid wild Brassica rapa (AA, 2n = 20) and the tetraploid cultivar B. napus (AACC, 2n = 38) can readily be made. Backcrosses to the wild B. rapa (BC1 ) produce aneuploids with variable chromosome numbers between 20 and 29. How does survival and performance relate to DNA content of plants? Growth of the BC1 plants was measured in the lab. One plant in the F1 self-pollinated spontaneously and produced abundant F2 seeds that were also examined. The number of C-chromosomes was estimated from DNA values obtained with flow cytometry. Average DNA value of the BC1 was similar to that of the parents, which shows that C-chromosomes do not reduce success of pollen or embryos. The average DNA value in the F2 was 13% higher than in the F1 , suggesting that extra C-chromosomes facilitated gamete success and/or embryo survival. Under both optimal and drought stress conditions growth and survival of BC1 hybrids was similar to that of B. rapa. No significant correlations existed between growth or survival and DNA value. Aneuploid plants were not inferior under the conditions of the growth room and may persist in nature. We discuss other factors, such as herbivory, that could prevent hybrid establishment in the field.
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Affiliation(s)
- T J de Jong
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands
| | | | | | - M Moshgani
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands
- Department of Environmental Science, Faculty of Agriculture, University of Birjand, Birjand, Iran
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12
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Ureta MS, Torres Carbonell F, Pandolfo C, Presotto AD, Cantamutto MA, Poverene M. IMI resistance associated to crop-weed hybridization in a natural Brassica rapa population: characterization and fate. Environ Monit Assess 2017; 189:101. [PMID: 28185156 DOI: 10.1007/s10661-016-5760-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 12/27/2016] [Indexed: 05/14/2023]
Abstract
Wild turnip (Brassica rapa) is a common weed and a close relative to oilseed rape (Brassica napus). The Clearfield® production system is a highly adopted tool which provides an alternative solution for weed management, but its efficiency is threatened by gene transfer from crop to weed relatives. Crop-weed hybrids with herbicide resistance were found in the progeny of a B. rapa population gathered from a weedy stand on the borders of an oilseed rape (B. napus) imidazolinone (IMI)-resistant crop. Interspecific hybrids were confirmed by morphological traits in the greenhouse and experimental field, survival after imazethapyr applications, DNA content through flow cytometry, and pollen viability. The transference of herbicide resistance was demonstrated even in a particular situation of pollen competition between both an herbicide-resistant crop and a non-resistant crop. However, IMI resistance was not found in further generations collected at the same location. These results verify gene transmission from oilseed rape to B. rapa in the main crop area in Argentina where resistant and susceptible varieties are found and seed loss and crop volunteers are common. Hybridization, introgression, and herbicide selection would be associated with the loss of effectiveness of IMI technology.
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Affiliation(s)
- M S Ureta
- Departamento de Agronomía, Universidad Nacional del Sur and CERZOS-CCT, 8000, Bahía Blanca, Argentina.
| | - F Torres Carbonell
- Departamento de Agronomía, Universidad Nacional del Sur and CERZOS-CCT, 8000, Bahía Blanca, Argentina
| | - C Pandolfo
- Departamento de Agronomía, Universidad Nacional del Sur and CERZOS-CCT, 8000, Bahía Blanca, Argentina
| | - A D Presotto
- Departamento de Agronomía, Universidad Nacional del Sur and CERZOS-CCT, 8000, Bahía Blanca, Argentina
| | - M A Cantamutto
- EEA INTA, Hilario Ascasubi, Ruta 3 km 794, Buenos Aires, Argentina
| | - M Poverene
- Departamento de Agronomía, Universidad Nacional del Sur and CERZOS-CCT, 8000, Bahía Blanca, Argentina
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Sohn SI, Oh YJ, Lee KR, Ko HC, Cho HS, Lee YH, Chang A. Characteristics Analysis of F1 Hybrids between Genetically Modified Brassica napus and B. rapa. PLoS One 2016; 11:e0162103. [PMID: 27632286 PMCID: PMC5025156 DOI: 10.1371/journal.pone.0162103] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 08/17/2016] [Indexed: 11/21/2022] Open
Abstract
A number of studies have been conducted on hybridization between transgenic Brassica napus and B. rapa or backcross of F1 hybrid to their parents. However, trait changes must be analyzed to evaluate hybrid sustainability in nature. In the present study, B. rapa and transgenic (BrAGL20) B. napus were hybridized to verify the early flowering phenomenon of F1 hybrids, and F1 hybrid traits were analyzed to predict their impact on sustainability. Flowering of F1 hybrid has been induced slightly later than that of the transgenic B. napus, but flowering was available in the greenhouse without low temperature treatment to young plant, similar to the transgenic B. napus. It is because the BrAGL20 gene has been transferred from transgenic B. napus to F1 hybrid. The size of F1 hybrid seeds was intermediate between those of B. rapa and transgenic B. napus, and ~40% of F1 pollen exhibited abnormal size and morphology. The form of the F1 stomata was also intermediate between that of B. rapa and transgenic B. napus, and the number of stomata was close to the parental mean. Among various fatty acids, the content of erucic acid exhibited the greatest change, owing to the polymorphism of parental FATTY ACID ELONGASE 1 alleles. Furthermore, F2 hybrids could not be obtained. However, BC1 progeny were obtained by hand pollination of B. rapa with F1 hybrid pollen, with an outcrossing rate of 50%.
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Affiliation(s)
- Soo-In Sohn
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, 370 Nongsaengmyeong-ro, Wansan-gu, Jeonju, North Jeolla Province, 54874, Republic of Korea
| | - Young-Ju Oh
- Institute for Future Environmental Ecology Co., Ltd, 5, Palbok 1-gil, Deokjin-gu, Jeonju, North Jeolla Province, 54883, Republic of Korea
| | - Kyeong-Ryeol Lee
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, 370 Nongsaengmyeong-ro, Wansan-gu, Jeonju, North Jeolla Province, 54874, Republic of Korea
| | - Ho-Cheol Ko
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, 370 Nongsaengmyeong-ro, Wansan-gu, Jeonju, North Jeolla Province, 54874, Republic of Korea
| | - Hyun-Suk Cho
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, 370 Nongsaengmyeong-ro, Wansan-gu, Jeonju, North Jeolla Province, 54874, Republic of Korea
| | - Yeon-Hee Lee
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, 370 Nongsaengmyeong-ro, Wansan-gu, Jeonju, North Jeolla Province, 54874, Republic of Korea
| | - Ancheol Chang
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, 370 Nongsaengmyeong-ro, Wansan-gu, Jeonju, North Jeolla Province, 54874, Republic of Korea
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Guan ZJ, Zhang PF, Wei W, Mi XC, Kang DM, Liu B. Performance of hybrid progeny formed between genetically modified herbicide-tolerant soybean and its wild ancestor. AoB Plants 2015; 7:plv121. [PMID: 26507568 PMCID: PMC4670487 DOI: 10.1093/aobpla/plv121] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 10/11/2015] [Indexed: 05/25/2023]
Abstract
Gene flow from genetically modified (GM) crops to wild relatives might affect the evolutionary dynamics of weedy populations and result in the persistence of escaped genes. To examine the effects of this gene flow, the growth of F1 hybrids that were formed by pollinating wild soybean (Glycine soja) with glyphosate-tolerant GM soybean (G. max) or its non-GM counterpart was examined in a greenhouse. The wild soybean was collected from two geographical populations in China. The performance of the wild soybean and the F2 hybrids was further explored in a field trial. Performance was measured by several vegetative and reproductive growth parameters, including the vegetative growth period, pod number, seed number, above-ground biomass and 100-seed weight. The pod setting percentage was very low in the hybrid plants. Genetically modified hybrid F1 plants had a significantly longer period of vegetative growth, higher biomass and lower 100-seed weight than the non-GM ones. The 100-seed weight of both F1 and F2 hybrids was significantly higher than that of wild soybean in both the greenhouse and the field trial. No difference in plant growth was found between GM and non-GM F2 hybrids in the field trial. The herbicide-resistant gene appeared not to adversely affect the growth of introgressed wild soybeans, suggesting that the escaped transgene could persist in nature in the absence of herbicide use.
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Affiliation(s)
- Zheng-Jun Guan
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China Department of Life Sciences, Yuncheng University, Yuncheng, Shanxi 044000, China
| | - Peng-Fei Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Wei Wei
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiang-Cheng Mi
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ding-Ming Kang
- College of Agriculture and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Biao Liu
- Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection of China, Nanjing, Jiangsu 210042, China
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Ford CS, Allainguillaume J, Fu TYR, Mitchley J, Wilkinson MJ. Assessing the value of imperfect biocontainment nationally: rapeseed in the United Kingdom as an exemplar. New Phytol 2015; 205:1342-1349. [PMID: 25367754 DOI: 10.1111/nph.13131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 09/21/2014] [Indexed: 06/04/2023]
Abstract
Paternal biocontainment methods (PBMs) act by preventing pollen-mediated transgene flow. They are compromised by transgene escape via the crop-maternal line. We therefore assess the efficacy of PBMs for transgenic rapeseed (Brassica napus) biocontainment across the United Kingdom by estimating crop-maternal hybridization with its two progenitor species. We used remote sensing, field surveys, agricultural statistics, and meta-analysis to determine the extent of sympatry between the crop and populations of riparian and weedy B. rapa and B. oleracea. We then estimated the incidence of crop-maternal hybridization across all settings to predict the efficacy of PBMs. Evidence of crop chloroplast capture by the progenitors was expanded to a national scale, revealing that crop-maternal gene flow occurs at widely variable rates and is dependent on both the recipient and setting. We use these data to explore the value that this kind of biocontainment can bring to genetic modification (GM) risk management in terms of reducing the impact that hybrids have on the environment rather than preventing or reducing hybrid abundance per se.
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Affiliation(s)
- Caroline S Ford
- School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA, 5064, Australia
| | - Joël Allainguillaume
- Department of Biological, Biomedical and Analytical Sciences, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK
| | - Tzu-Yu Richard Fu
- Department of International Affairs, Council of Agriculture, Executive Yuan, Taipei, Taiwan
| | - Jonathan Mitchley
- School of Biological Sciences, University of Reading, Whiteknights, Reading, RG6 6AS, UK
| | - Mike J Wilkinson
- School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA, 5064, Australia
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Hooftman DAP, Bullock JM, Morley K, Lamb C, Hodgson DJ, Bell P, Thomas J, Hails RS. Seed bank dynamics govern persistence of Brassica hybrids in crop and natural habitats. Ann Bot 2015; 115:147-157. [PMID: 25452253 PMCID: PMC4284111 DOI: 10.1093/aob/mcu213] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/26/2014] [Accepted: 09/16/2014] [Indexed: 06/04/2023]
Abstract
BACKGROUND AND AIMS Gene flow from crops to their wild relatives has the potential to alter population growth rates and demography of hybrid populations, especially when a new crop has been genetically modified (GM). This study introduces a comprehensive approach to assess this potential for altered population fitness, and uses a combination of demographic data in two habitat types and mathematical (matrix) models that include crop rotations and outcrossing between parental species. METHODS Full life-cycle demographic rates, including seed bank survival, of non-GM Brassica rapa × B. napus F1 hybrids and their parent species were estimated from experiments in both agricultural and semi-natural habitats. Altered fitness potential was modelled using periodic matrices including crop rotations and outcrossing between parent species. KEY RESULTS The demographic vital rates (i.e. for major stage transitions) of the hybrid population were intermediate between or lower than both parental species. The population growth rate (λ) of hybrids indicated decreases in both habitat types, and in a semi-natural habitat hybrids became extinct at two sites. Elasticity analyses indicated that seed bank survival was the greatest contributor to λ. In agricultural habitats, hybrid populations were projected to decline, but with persistence times up to 20 years. The seed bank survival rate was the main driver determining persistence. It was found that λ of the hybrids was largely determined by parental seed bank survival and subsequent replenishment of the hybrid population through outcrossing of B. rapa with B. napus. CONCLUSIONS Hybrid persistence was found to be highly dependent on the seed bank, suggesting that targeting hybrid seed survival could be an important management option in controlling hybrid persistence. For local risk mitigation, an increased focus on the wild parent is suggested. Management actions, such as control of B. rapa, could indirectly reduce hybrid populations by blocking hybrid replenishment.
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Affiliation(s)
- Danny A P Hooftman
- Centre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UK, School of Biosciences, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, UK and National Institute of Agricultural Botany, Huntingdon Rd, Cambridge CB3 0EL, UK
| | - James M Bullock
- Centre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UK, School of Biosciences, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, UK and National Institute of Agricultural Botany, Huntingdon Rd, Cambridge CB3 0EL, UK
| | - Kathryn Morley
- Centre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UK, School of Biosciences, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, UK and National Institute of Agricultural Botany, Huntingdon Rd, Cambridge CB3 0EL, UK
| | - Caroline Lamb
- Centre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UK, School of Biosciences, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, UK and National Institute of Agricultural Botany, Huntingdon Rd, Cambridge CB3 0EL, UK
| | - David J Hodgson
- Centre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UK, School of Biosciences, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, UK and National Institute of Agricultural Botany, Huntingdon Rd, Cambridge CB3 0EL, UK
| | - Philippa Bell
- Centre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UK, School of Biosciences, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, UK and National Institute of Agricultural Botany, Huntingdon Rd, Cambridge CB3 0EL, UK
| | - Jane Thomas
- Centre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UK, School of Biosciences, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, UK and National Institute of Agricultural Botany, Huntingdon Rd, Cambridge CB3 0EL, UK
| | - Rosemary S Hails
- Centre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UK, School of Biosciences, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, UK and National Institute of Agricultural Botany, Huntingdon Rd, Cambridge CB3 0EL, UK
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17
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Luijten SH, Schidlo NS, Meirmans PG, de Jong TJ. Hybridisation and introgression between Brassica napus and B. rapa in the Netherlands. Plant Biol (Stuttg) 2015; 17:262-267. [PMID: 24889091 DOI: 10.1111/plb.12197] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 03/23/2014] [Indexed: 06/03/2023]
Abstract
We used flow cytometry, chromosome counting and AFLP markers to investigate gene flow from the crop plant oilseed rape, Brassica napus (AACC) to wild B. rapa (AA) in the Netherlands. From 89 B. napus source populations investigated, all near cropping fields or at transhipment sites, only 19 contained a B. rapa population within a 2.5-km radius. During our survey we found only three populations with F1 hybrids (AAC), as recognized by their nine extra chromosomes and by flow cytometry. These hybrids were all collected in mixed populations where the two species grew in close proximity. Populations with F1 hybrids were not close to crops, but instead were located on road verges with highly disturbed soils, in which both species were probably recruited from the soil seed bank. Many plants in the F2, BC1 or higher backcrosses are expected to carry one to eight C chromosomes. However, these plants were not observed among the hybrids. We further investigated introgression with molecular markers (AFLP) and compared sympatric B. rapa populations (near populations of B. napus) with control populations of B. rapa (no B. napus within at least 7 km). We found no difference between sympatric and control populations in the number of C markers in B. rapa, nor did we find that these sympatric populations closely resembled B. napus. Our data show that hybrids occur but also suggest no recent introgression of alleles from the crop plant B. napus into wild B. rapa in the Dutch populations studied.
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Affiliation(s)
- S H Luijten
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands; Science4Nature, Science Park 904, 1098 XH, Amsterdam, the Netherlands
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18
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Cao D, Stewart CN, Zheng M, Guan Z, Tang ZX, Wei W, Ma KP. Stable Bacillus thuringiensis transgene introgression from Brassica napus to wild mustard B. juncea. Plant Sci 2014; 227:45-50. [PMID: 25219305 DOI: 10.1016/j.plantsci.2014.06.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/27/2014] [Accepted: 06/28/2014] [Indexed: 06/03/2023]
Abstract
Transgenic canola (Brassica napus) with a Bacillus thuringiensis cry1Ac gene and a green fluorescent protein (GFP) marker gene was used in hybridization experiments with wild Brassica juncea. Hybrid F1 and successive five backcross generations were obtained. The pod-set frequency on backcrossed B. juncea plants was over 66%, which suggested relatively high crossing compatibility between the hybrids and wild species. The seed setting in BC1 was the least of all generations tested, and then increased at the BC2 generation for which the thousand-seed weight was the highest of all generations. Seed size in backcrossed generations eventually approached that of the wild parent. The plants in all backcrossed generations were consistent with the expected 1:1 segregation ratio of the transgenes. The Bt Cry1Ac protein concentrations at bolting and flowering stages was higher compared to the 4-5-leaf and pod-formation stages. Nonetheless, the Bt toxin in the fifth backcrossing generation (BC5) was sufficient to kill both polyphagous (Helicoverpa armigera) and oligophagous (Plutella xylostella) Lepidoptera. As a consequence, the subsequent generations harboring the transgene from F1 to BC5 could have selection advantage against insect pests. The result is useful in understanding gene flow from transgenic crops and the followed transgene introgression into wild.
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Affiliation(s)
- Di Cao
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China
| | - C Neal Stewart
- Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA
| | - Min Zheng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China
| | - Zhengjun Guan
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China
| | - Zhi-Xi Tang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China
| | - Wei Wei
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
| | - Ke-Ping Ma
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China
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19
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Statement on a conceptual framework for the risk assessment of certain food additives re‐evaluated under Commission Regulation (EU) No 257/2010. EFSA J 2014. [DOI: 10.2903/j.efsa.2014.3697] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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20
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Scientific Opinion on application (EFSA‐GMO‐BE‐2011‐101) for the placing on the market of herbicide‐tolerant genetically modified oilseed rape MON 88302 for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Monsanto. EFSA J 2014. [DOI: 10.2903/j.efsa.2014.3701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Dechaine JM, Brock MT, Weinig C. QTL architecture of reproductive fitness characters in Brassica rapa. BMC Plant Biol 2014; 14:66. [PMID: 24641198 PMCID: PMC4004417 DOI: 10.1186/1471-2229-14-66] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 03/03/2014] [Indexed: 05/19/2023]
Abstract
BACKGROUND Reproductive output is critical to both agronomists seeking to increase seed yield and to evolutionary biologists interested in understanding natural selection. We examine the genetic architecture of diverse reproductive fitness traits in recombinant inbred lines (RILs) developed from a crop (seed oil) × wild-like (rapid cycling) genotype of Brassica rapa in field and greenhouse environments. RESULTS Several fitness traits showed strong correlations and QTL-colocalization across environments (days to bolting, fruit length and seed color). Total fruit number was uncorrelated across environments and most QTL affecting this trait were correspondingly environment-specific. Most fitness components were positively correlated, consistent with life-history theory that genotypic variation in resource acquisition masks tradeoffs. Finally, we detected evidence of transgenerational pleiotropy, that is, maternal days to bolting was negatively correlated with days to offspring germination. A QTL for this transgenerational correlation was mapped to a genomic region harboring one copy of FLOWERING LOCUS C, a genetic locus known to affect both days to flowering as well as germination phenotypes. CONCLUSIONS This study characterizes the genetic structure of important fitness/yield traits within and between generations in B. rapa. Several identified QTL are suitable candidates for fine-mapping for the improvement of yield in crop Brassicas. Specifically, brFLC1, warrants further investigation as a potential regulator of phenology between generations.
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Affiliation(s)
- Jennifer M Dechaine
- Department of Biological Sciences, Central Washington University, Ellensburg, WA 98926, USA
| | - Marcus T Brock
- Department of Botany, University of Wyoming, Laramie, WY 82071, USA
| | - Cynthia Weinig
- Department of Botany, University of Wyoming, Laramie, WY 82071, USA
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Liu Y, Wei W, Ma K, Li J, Liang Y, Darmency H. Consequences of gene flow between oilseed rape (Brassica napus) and its relatives. Plant Sci 2013; 211:42-51. [PMID: 23987810 DOI: 10.1016/j.plantsci.2013.07.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 07/04/2013] [Accepted: 07/06/2013] [Indexed: 06/02/2023]
Abstract
Numerous studies have focused on the probability of occurrence of gene flow between transgenic crops and their wild relatives and the likelihood of transgene escape, which should be assessed before the commercial release of transgenic crops. This review paper focuses on this issue for oilseed rape, Brassica napus L., a species that produces huge numbers of pollen grains and seeds. We analyze separately the distinct steps of gene flow: (1) pollen and seeds as vectors of gene flow; (2) spontaneous hybridization; (3) hybrid behavior, fitness cost due to hybridization and mechanisms of introgression; (4) and fitness benefit due to transgenes (e.g. herbicide resistance and Bt toxin). Some physical, biological and molecular means of transgene containment are also described. Although hybrids and first generation progeny are difficult to identify in fields and non-crop habitats, the literature shows that transgenes could readily introgress into Brassica rapa, Brassica juncea and Brassica oleracea, while introgression is expected to be rare with Brassica nigra, Hirschfeldia incana and Raphanus raphanistrum. The hybrids grow well but produce less seed than their wild parent. The difference declines with increasing generations. However, there is large uncertainty about the evolution of chromosome numbers and recombination, and many parameters of life history traits of hybrids and progeny are not determined with satisfactory confidence to build generic models capable to really cover the wide diversity of situations. We show that more studies are needed to strengthen and organize biological knowledge, which is a necessary prerequisite for model simulations to assess the practical and evolutionary outputs of introgression, and to provide guidelines for gene flow management.
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Affiliation(s)
- Yongbo Liu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
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Abstract
Pollen of the crop oilseed rape (Brassica napus, AACC) can cross-fertilize ovules of Brassica rapa (AA), which leads to an influx of unpaired C-chromosomes into wild B. rapa populations. The presence of such extra chromosomes is thought to be an indicator of introgression. Backcrosses and F(1) hybrids were found in Danish populations but, surprisingly, only F(1) hybrids were found in the UK and the Netherlands. Here, a model tests how the level of selection and biased vs unbiased transmission affect the population frequency of C-chromosomes. In the biased-transmission scenario the experimental results of the first backcross are extrapolated to estimate survival of gametes with different numbers of C-chromosomes from all crosses in the population. With biased transmission, the frequency of C-chromosomes always rapidly declines to zero. With unbiased transmission, the continued presence of plants with extra C-chromosomes depends on selection in the adult stage and we argue that this is the most realistic option for modeling populations. We suggest that selection in the field against plants with unpaired C-chromosomes is strong in Dutch and UK populations. The model highlights what we do not know and makes suggestions for further research on introgression.
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Affiliation(s)
- Tom J de Jong
- Plant Ecology & Phytochemistry, Institute of Biology Leiden, Leiden University, PO Box 9516, 2300RA Leiden, the Netherlands
| | - Elze Hesse
- Plant Ecology & Phytochemistry, Institute of Biology Leiden, Leiden University, PO Box 9516, 2300RA Leiden, the Netherlands
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Abstract
Transgenic plants have increased interest in the study of crop gene introgression in wild populations. Genes (or transgenes) conferring adaptive advantages persist in introgressed populations, enhancing competitiveness of wild or weedy plants. This represents an ecological risk that could increase problems of weed control. Introgression of cultivar alleles into wild plant populations via crop-wild hybridisations is primarily governed by their fitness effect. To evaluate this, we studied the second generation of seven wild-crop interspecific hybrids between weedy Helianthus petiolaris and cultivated sunflower, H. annuus var. macrocarpus. The second generation comprised open-pollinated progeny and backcrosses to the wild parent, mimicking crosses that occur in natural situations. We compared a number of morphological, life history and fitness traits. Multivariate analysis showed that the parental species H. annuus and H. petiolaris differed in a number of morphological traits, while the second hybrid generation between them was intermediate. Sunflower crop introgression lowered fitness of interspecific hybrids, but fitness parameters tended to recover in the following generation. Relative frequency of wild/weedy and introgressed plants was estimated through four generations, based on male and female parent fitness. In spite of several negative selection coefficients observed in the second generation, introgressed plants could be detected in stands of <100 weedy H. petiolaris populations. The rapid recovery of fecundity parameters leads to prediction that any trait conferring an ecological advantage will diffuse into the wild or weedy population, even if F1 hybrids have low fitness.
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Affiliation(s)
- A Gutierrez
- Centro De Recursos Naturales de la Zona Semiárida (CERZOS-CONICET), Bahía Blanca, Argentina.
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Rader R, Edwards W, Westcott DA, Cunningham SA, Howlett BG. Pollen transport differs among bees and flies in a human-modified landscape. DIVERS DISTRIB 2011. [DOI: 10.1111/j.1472-4642.2011.00757.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Watrud LS, King G, Londo JP, Colasanti R, Smith BM, Waschmann RS, Lee EH. Changes in constructed Brassica communities treated with glyphosate drift. Ecol Appl 2011; 21:525-38. [PMID: 21563582 DOI: 10.1890/09-2366.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We constructed a mixed-species community designed to simulate roadside and field edge plant communities and exposed it to glyphosate drift in order to test three hypotheses: (1) higher fitness in transgenic Brassica carrying the CP4 EPSPS transgene that confers resistance to glyphosate will result in significant changes in the plant community relative to control communities; (2) given repeated years of glyphosate drift selective pressure, the increased fitness of the transgenic Brassica with CP4 EPSPS will contribute to an increase in the proportion of transgenic progeny produced in plant communities; and (3) the increased fitness of Brassica carrying the CP4 EPSPS transgene will contribute to decreased levels of mycorrhizal infection and biomass in a host species (Trifolium incarnatum). Due to regulatory constraints that prevented the use of outdoor plots for our studies, in 2005 we established multispecies communities in five large cylindrical outdoor sunlit mesocosms (plastic greenhouses) designed for pollen confinement. Three of the community members were sexually compatible Brassica spp.: transgenic glyphosate-resistant canola (B. napus) cultivar (cv.) RaideRR, glyphosate-sensitive non-transgenic B. napus cv. Sponsor, and a weedy B. rapa (GRIN Accession 21735). Additional plant community members were the broadly distributed annual weeds Digitaria sanguinalis, Panicum capillare, and Lapsana communis. Once annually in 2006 and 2007, two mesocosms were sprayed with glyphosate at 10% of the field application rate to simulate glyphosate drift as a selective pressure. After two years, changes were observed in community composition, plant density, and biomass in both control and treatment mesocosms. In control mesocosms, the weed D. sanguinalis (crabgrass) began to dominate. In glyphosate drift-treated mesocosms, Brassica remained the dominant genus and the incidence of the CP4 EPSPS transgene increased in the community. Shoot biomass and mycorrhizal infection in Trifolium incarnatum planted in 2008 were significantly lower in mesocosms that had received glyphosate drift treatments. Our results suggest that, over time, glyphosate drift can contribute to persistence of Brassica that express the CP4 EPSPS transgene and that increased representation of Brassica (a non-mycorrhizal host) within plant communities may indirectly negatively impact beneficial ecosystem services associated with arbuscular mycorrhiza.
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Affiliation(s)
- Lidia S Watrud
- U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, 200 SW 35th Street, Corvallis, Oregon 97333, USA.
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Vacher C, Kossler TM, Hochberg ME, Weis AE. Impact of interspecific hybridization between crops and weedy relatives on the evolution of flowering time in weedy phenotypes. PLoS One 2011; 6:e14649. [PMID: 21304909 PMCID: PMC3033403 DOI: 10.1371/journal.pone.0014649] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 01/03/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Like conventional crops, some GM cultivars may readily hybridize with their wild or weedy relatives. The progressive introgression of transgenes into wild or weedy populations thus appears inevitable, and we are now faced with the challenge of determining the possible evolutionary effects of these transgenes. The aim of this study was to gain insight into the impact of interspecific hybridization between transgenic plants and weedy relatives on the evolution of the weedy phenotype. METHODOLOGY/PRINCIPAL FINDINGS Experimental populations of weedy birdseed rape (Brassica rapa) and transgenic rapeseed (B. napus) were grown under glasshouse conditions. Hybridization opportunities with transgenic plants and phenotypic traits (including phenological, morphological and reproductive traits) were measured for each weedy individual. We show that weedy individuals that flowered later and for longer periods were more likely to receive transgenic pollen from crops and weed × crop hybrids. Because stem diameter is correlated with flowering time, plants with wider stems were also more likely to be pollinated by transgenic plants. We also show that the weedy plants with the highest probability of hybridization had the lowest fecundity. CONCLUSION/SIGNIFICANCE Our results suggest that weeds flowering late and for long periods are less fit because they have a higher probability of hybridizing with crops or weed × crop hybrids. This may result in counter-selection against this subset of weed phenotypes, and a shorter earlier flowering period. It is noteworthy that this potential evolution in flowering time does not depend on the presence of the transgene in the crop. Evolution in flowering time may even be counter-balanced by positive selection acting on the transgene if the latter was positively associated with maternal genes promoting late flowering and long flowering periods. Unfortunately, we could not verify this association in the present experiment.
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Affiliation(s)
- Corinne Vacher
- INRA, UMR1202 Biodiversité Gènes et Communautés, Cestas, France.
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Londo JP, Bautista NS, Sagers CL, Lee EH, Watrud LS. Glyphosate drift promotes changes in fitness and transgene gene flow in canola (Brassica napus) and hybrids. Ann Bot 2010; 106:957-65. [PMID: 20852306 PMCID: PMC2990662 DOI: 10.1093/aob/mcq190] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 08/17/2010] [Accepted: 08/23/2010] [Indexed: 05/26/2023]
Abstract
BACKGROUND AND AIMS With the advent of transgenic crops, genetically modified, herbicide-resistant Brassica napus has become a model system for examining the risks and potential ecological consequences of escape of transgenes from cultivation into wild compatible species. Escaped transgenic feral B. napus and hybrids with compatible weedy species have been identified outside of agriculture and without the apparent selection for herbicide resistance. However, herbicide (glyphosate) exposure can extend beyond crop field boundaries, and a drift-level of herbicide could function as a selective agent contributing to increased persistence of transgenes in the environment. METHODS The effects of a drift level (0·1 × the field application rate) of glyphosate herbicide and varied levels of plant competition were examined on plant fitness-associated traits and gene flow in a simulated field plot, common garden experiment. Plants included transgenic, glyphosate-resistant B. napus, its weedy ancestor B. rapa, and hybrid and advanced generations derived from them. KEY RESULTS The results of this experiment demonstrate reductions in reproductive fitness for non-transgenic genotypes and a contrasting increase in plant fitness for transgenic genotypes as a result of glyphosate-drift treatments. Results also suggest that a drift level of glyphosate spray may influence the movement of transgenes among transgenic crops and weeds and alter the processes of hybridization and introgression in non-agronomic habitats by impacting flowering phenology and pollen availability within the community. CONCLUSIONS The results of this study demonstrate the potential for persistence of glyphosate resistance transgenes in weedy plant communities due to the effect of glyphosate spray drift on plant fitness. Additionally, glyphosate drift has the potential to change the gene-flow dynamics between compatible transgenic crops and weeds, simultaneously reducing direct introgression into weedy species while contributing to an increase in the transgenic seed bank.
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Affiliation(s)
- Jason P Londo
- National Research Council Associate, 200 SW 35th Street, Corvallis, OR 97333, USA.
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Liu YB, Wei W, Ma KP, Darmency H. Backcrosses to Brassica napus of hybrids between B. juncea and B. napus as a source of herbicide-resistant volunteer-like feral populations. Plant Sci 2010; 179:459-465. [PMID: 21802604 DOI: 10.1016/j.plantsci.2010.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 07/05/2010] [Accepted: 07/08/2010] [Indexed: 05/31/2023]
Abstract
Introgression between genetically modified (GM) crops and wild relatives is considered to potentially modify the genetic background of the wild species. The emergence of volunteer-like feral populations through backcross of hybrids to the crop is also a concern. The progeny of spontaneous hybrids between mutant herbicide-resistant oilseed rape (Brassica napus) and wild B. juncea was obtained. Parents, F(2) and BC(1) to B. napus were planted together in the field so as to study their performance. The chromosome number of BC(1) followed a Normal distribution. Mendelian ratio of the herbicide-resistance gene was found. The F(2) produced less seeds than B. napus, and BC(1) had intermediate production. Herbicide-resistant BC(1) were not different of their susceptible counterparts for plant weight, seed weight and seed number, but most of them exhibited B. napus morphology and larger flowers than the susceptible BC(1). They displayed an important genetic variability allowing further adaptation and propagation of the herbicide-resistance gene. Pollen flow to susceptible plants within the mixed stand was observed. As a consequence, the resistant BC(1) produced with B. napus pollen could frequently occur and easily establish as a false feral crop population within fields and along roadsides.
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Affiliation(s)
- Y B Liu
- INRA, UMR 1210, Biologie et Gestion des Adventices, Institut National de la Recherche Agronomique, 17 rue Sully, Dijon BP 86510, 21065, France; National Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Science, 20 Nanxincun, Beijing 100093, PR China
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Abstract
The main environmental concerns about genetically modified (GM) crops are the potential weediness or invasiveness in the crop itself or in its wild or weedy relatives as a result of transgene movement. Here we briefly review evidence for pollen- and seed-mediated gene flow from GM crops to non-GM or other GM crops and to wild relatives. The report focuses on the effect of abiotic and biotic stress-tolerance traits on plant fitness and their potential to increase weedy or invasive tendencies. An evaluation of weediness and invasive traits that contribute to the success of agricultural weeds and invasive plants was of limited value in predicting the effect of biotic and abiotic stress-tolerance GM traits, suggesting context-specific evaluation rather than generalizations. Fitness data on herbicide, insect, and disease resistance, as well as cold-, drought-, and salinity-tolerance traits, are reviewed. We describe useful ecological models predicting the effects of gene flow and altered fitness in GM crops and wild/weedy relatives, as well as suitable mitigation measures. A better understanding of factors controlling population size, dynamics, and range limits in weedy volunteer GM crop and related host or target weed populations is necessary before the effect of biotic and abiotic stress-tolerance GM traits can be fully assessed.
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Affiliation(s)
- Suzanne I Warwick
- Agriculture and Agri-Food Canada, Eastern Cereal and Oilseeds Research Centre, Ottawa, Ontario, Canada.
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Allainguillaume J, Harwood T, Ford CS, Cuccato G, Norris C, Allender CJ, Welters R, King GJ, Wilkinson MJ. Rapeseed cytoplasm gives advantage in wild relatives and complicates genetically modified crop biocontainment. New Phytol 2009; 183:1201-1211. [PMID: 19496946 DOI: 10.1111/j.1469-8137.2009.02877.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Biocontainment methods for genetically modified crops closest to commercial reality (chloroplast transformation, male sterility) would be compromised (in absolute terms) by seed-mediated gene flow leading to chloroplast capture. Even in these circumstances, however, it can be argued that biocontainment still represses transgene movement, with the efficacy depending on the relative frequency of seed- and pollen-mediated gene flow. In this study, we screened for crop-specific chloroplast markers from rapeseed (Brassica napus) amongst sympatric and allopatric populations of wild B. oleracea in natural cliff-top populations and B. rapa in riverside and weedy populations. We found only modest crop chloroplast presence in wild B. oleracea and in weedy B. rapa, but a surprisingly high incidence in sympatric (but not in allopatric) riverside B. rapa populations. Chloroplast inheritance models indicate that elevated crop chloroplast acquisition is best explained if crop cytoplasm confers selective advantage in riverside B. rapa populations. Our results therefore imply that chloroplast transformation may slow transgene recruitment in two settings, but actually accelerate transgene spread in a third. This finding suggests that the appropriateness of chloroplast transformation for biocontainment policy depends on both context and geographical location.
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Affiliation(s)
- J Allainguillaume
- School of Biological Sciences, The University of Reading, Reading, Berkshire RG6 6AS, UK
| | - T Harwood
- Centre for Environmental Policy, Imperial College London, London SL5 7PY, UK
| | - C S Ford
- School of Biological Sciences, The University of Reading, Reading, Berkshire RG6 6AS, UK
| | - G Cuccato
- School of Biological Sciences, The University of Reading, Reading, Berkshire RG6 6AS, UK
| | - C Norris
- National Institute of Agricultural Botany (NIAB), Cambridge, Cambridgeshire CB3 0LE, UK
| | - C J Allender
- Warwick HRI, Wellesbourne, Warwickshire CV35 9EF, UK
| | - R Welters
- Natural Environment Research Council, Swindon, Berkshire SN2 1EU, UK
| | - G J King
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - M J Wilkinson
- School of Biological Sciences, The University of Reading, Reading, Berkshire RG6 6AS, UK
- Present address: Institute of Biological, Environmental and Rural Sciences, Edward Llwyd Building, Aberystwyth University, Aberystwyth SY23 3DA, UK
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Jørgensen RB, Hauser T, D'Hertefeldt T, Andersen NS, Hooftman D. The variability of processes involved in transgene dispersal-case studies from Brassica and related genera. Environ Sci Pollut Res Int 2009; 16:389-395. [PMID: 19387714 DOI: 10.1007/s11356-009-0142-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2008] [Accepted: 03/02/2009] [Indexed: 05/27/2023]
Abstract
BACKGROUND, AIM, AND SCOPE We strive to predict consequences of genetically modified plants (GMPs) being cultivated openly in the environment, as human and animal health, biodiversity, agricultural practise and farmers' economy could be affected. Therefore, it is unfortunate that the risk assessment of GMPs is burdened by uncertainty. One of the reasons for the uncertainty is that the GMPs are interacting with the ecosystems at the release site thereby creating variability. This variability, e.g. in gene flow, makes consequence analysis difficult. The review illustrates the great uncertainty of results from gene-flow analysis. MAIN FEATURES Many independent experiments were performed on the individual processes in gene flow. The results comprise information both from laboratory, growth chambers and field trials, and they were generated using molecular or phenotypic markers and analysis of fitness parameters. Monitoring of the extent of spontaneous introgression in natural populations was also performed. Modelling was used as an additional tool to identify key parameters in gene flow. RESULTS The GM plant may affect the environment directly or indirectly by dispersal of the transgene. Magnitude of the transgene dispersal will depend on the GM crop, the agricultural practise and the environment of the release site. From case-to-case these three factors provide a variability that is reflected in widely different likelihoods of transgene dispersal and fitness of introgressed plants. In the present review, this is illustrated through a bunch of examples mostly from our own research on oilseed rape, Brassica napus. In the Brassica cases, the variability affected all five main steps in the process of gene dispersal. The modelling performed suggests that in Brassica, differences in fitness among plant genome classes could be a dominant factor in the establishment and survival of introgressed populations. DISCUSSION Up to now, experimental analyses have mainly focused on studying the many individual processes of gene flow. This can be criticised, as these experiments are normally carried out in widely different environments and with different genotypes, and thus providing bits and pieces difficult to assemble. Only few gene-flow studies have been performed in natural populations and over several plant generations, though this could give a more coherent and holistic view. CONCLUSION The variability inherent in the processes of gene flow in Brassica is apparent and remedies are wished for. One possibility is to expose the study species to additional experiments and monitoring, but this is costly and will likely not cover all possible scenarios. Another remedy is modelling gene flow. Modelling is a valuable tool in identifying key factors in the gene-flow process for which more knowledge is needed, and identifying parameters and processes which are relatively insensitive to change and therefore require less attention in future collections of data. But the interdependence between models and experimental data is extensive, as models depend on experimental data for their development or testing. RECOMMENDATIONS More and more transgenic varieties are being grown worldwide harbouring genes that might potentially affect the environment (e.g. drought tolerance, salt tolerance, disease tolerance, pharmaceutical genes). This calls for a thorough risk assessment. However, in Brassica, the limited and uncertain knowledge on gene flow is an obstacle to this. Modelling of gene flow should be optimised, and modelling outputs verified in targeted field studies and at the landscape level. Last but not least, it is important to remember that transgene flow in itself is not necessarily a thread, but it is the consequences of gene flow that may jeopardise the ecosystems and the agricultural production. This emphasises the importance of consequence analysis of genetically modified plants.
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Affiliation(s)
- Rikke Bagger Jørgensen
- National Laboratory of Sustainable Energy, Risø DTU, Frederiksborgvej 399, 4000, Roskilde, Denmark.
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Abstract
Risk assessments of new insect-resistant crops will need to estimate the potential for increased weediness of wild crop relatives as a consequence of gene flow. When field experiments are precluded by containment concerns, simulation experiments can identify hazards or measure expected differences between GMOs and parental plants. To measure plant fitness consequences of wild plant protection from Bt-susceptible herbivores, we used topical sprays of bacterial Bacillus thuringiensis larvacide (Bt) on Brassica rapa. Spontaneous crosses between B. rapa and Bt cole crops cannot be precluded, especially if adoption of Bt varieties leads to high exposure. We compared survivorship and seed output of B. rapa that were either protected from or exposed to Bt-susceptible Lepidoptera in the various conditions where hybrids are likely to occur: cultivated (disked) soil, uncultivated agricultural field margins, and nearby non-crop habitats (meadows and ruderal areas). The relative effect of herbivore protection varied among years, habitats, and populations of seedlings. In 2003-2004, Bt sprays did not result in lower herbivory on B. rapa, and plant fitness was not increased. However, in 2004-2006 B. rapa seedlings protected from Bt-susceptible herbivores lived 25% longer, on average, than those that were exposed to these herbivores. In addition, an average B. rapa seedling sprayed with Bt throughout its lifetime was twice as likely to produce siliques and had 251% of the seed output of a seedling exposed to herbivores. The fitness advantage of Bt-based plant protection was apparent in 2004-2005 in half the plants that experienced higher herbivory, and for 2005-2006, was more pronounced in agricultural habitats than in meadows with established, perennial vegetation and less disturbance. Positive effects of Bt-based plant protection and greater fitness in disturbed habitats suggest that crop-wild gene flow may benefit weed populations, and that field tests with herbivore exclusion/addition experiments are feasible alternatives when molecular containment of transgenes restricts field experiments with insect resistant crop-wild hybrids.
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Affiliation(s)
- Deborah K Letourneau
- Department of Environmental Studies, University of California, Santa Cruz, CA 95064, USA.
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Nishizawa T, Nakajima N, Aono M, Tamaoki M, Kubo A, Saji H. Monitoring the occurrence of genetically modified oilseed rape growing along a Japanese roadside: 3-year observations. ACTA ACUST UNITED AC 2009; 8:33-44. [DOI: 10.1051/ebr/2009001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Haider N, Allainguillaume J, Wilkinson MJ. Spontaneous capture of oilseed rape (Brassica napus) chloroplasts by wild B. rapa: implications for the use of chloroplast transformation for biocontainment. Curr Genet 2009; 55:139-50. [PMID: 19198841 DOI: 10.1007/s00294-009-0230-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 01/13/2009] [Accepted: 01/16/2009] [Indexed: 10/21/2022]
Abstract
Environmental concerns over the cultivation of Genetically Modified (GM) crops largely centre on the ecological consequences following gene flow to wild relatives. One attractive solution is to deploy biocontainment measures that prevent hybridization. Chloroplast transformation is the most advanced biocontainment method but is compromised by chloroplast capture (hybridization through the maternal lineage). To date, however, there is a paucity of information on the frequency of chloroplast capture in the wild. Oilseed rape (Brassica napus, AACC) frequently hybridises with wild Brassica rapa (AA, as paternal parent) and yields B. rapa-like introgressed individuals after only two generations. In this study we used chloroplast CAPS markers that differentiate between the two species to survey wild and weedy populations of B. rapa for the capture of B. napus chloroplasts. A total of 464 B. rapa plants belonging to 14 populations growing either in close proximity to B. napus (i.e. sympatric <5 m) or else were allopatric from the crop (>1 km) were assessed for chloroplast capture using PCR (trnL-F) and CAPS (trnT-L-Xba I) markers. The screen revealed that two sympatric B. rapa populations included 53 plants that possessed the chloroplast of B. napus. In order to discount these B. rapa plants as F(1) crop-wild hybrids, we used a C-genome-specific marker and found that 45 out of 53 plants lacked the C-genome and so were at least second generation introgressants. The most plausible explanation is that these individuals represent multiple cases of chloroplast capture following introgressive hybridisation through the female germ line from the crop. The abundance of such plants in sympatric sites thereby questions whether the use of chloroplast transformation would provide a sufficient biocontainment for GM oilseed rape in the United Kingdom.
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Devos Y, De Schrijver A, Reheul D. Quantifying the introgressive hybridisation propensity between transgenic oilseed rape and its wild/weedy relatives. Environ Monit Assess 2009; 149:303-322. [PMID: 18253849 DOI: 10.1007/s10661-008-0204-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 01/16/2008] [Indexed: 05/25/2023]
Abstract
In order to estimate the introgressive hybridisation propensity (IHP) between genetically modified (GM) oilseed rape (Brassica napus) and certain of its cross-compatible wild/weedy relatives at the landscape level, a conceptual approach was developed. A gene flow index was established enclosing the successive steps to successfully achieve introgressive hybridisation: wild/weedy relatives and oilseed rape should co-occur, have overlapping flowering periods, be compatible, produce viable and fertile progeny, and the transgenes should persist in natural/weedy populations. Each step was described and scored, resulting in an IHP value for each cross-compatible oilseed rape wild/weedy relative. The gene flow index revealed that Brassica rapa has the highest introgressive hybridisation propensity (IHP value = 11.5), followed by Hirschfeldia incana and Raphanus raphanistrum (IHP = 6.7), Brassica juncea (IHP = 5.1), Diplotaxis tenuifolia and Sinapis arvensis (IHP = 4.5) in Flanders. Based on the IHP values, monitoring priorities can be defined within the pool of cross-compatible wild/weedy oilseed rape relatives. Moreover, the developed approach enables to select areas where case-specific monitoring of GM oilseed rape could be done in order to detect potential adverse effects on cross-compatible wild/weedy relatives resulting from vertical gene flow. The implementation of the proposed oilseed rape-wild relative gene flow index revealed that the survey design of existing botanical survey networks does not suit general surveillance needs of GM crops in Belgium. The encountered hurdles to implement the gene flow index and proposals to acquire the missing data are discussed.
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Affiliation(s)
- Yann Devos
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
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Affiliation(s)
- Kristin L Mercer
- The Ohio State University, Department of Horticulture and Crop Science, 310D Kottman Hall, 2021 Coffey Road, Columbus, OH 43210, USA (tel +1 614 247-6394; email )
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Cai L, Zhou B, Guo X, Dong C, Hu X, Hou M, Liu S. Pollen-mediated gene flow in Chinese commercial fields of glufosinate-resistant canola (Brassica napus). Sci Bull (Beijing) 2008. [DOI: 10.1007/s11434-008-0305-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Hooftman DAP, Oostermeijer JGB, Marquard E, den Nijs H(JC. Modelling the consequences of cropwild relative gene flow: a sensitivity analysis of the effects of outcrossing rates and hybrid vigour breakdown inLactuca. J Appl Ecol 2008. [DOI: 10.1111/j.1365-2664.2008.01508.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
The strength and extent of gene flow from crops into wild populations depends, in part, on the fitness of the crop alleles, as well as that of alleles at linked loci. Interest in crop-wild gene flow has increased with the advent of transgenic plants, but nontransgenic crop-wild hybrids can provide case studies to understand the factors influencing introgression, provided that the genetic architecture and the fitness effects of loci are known. This study used recombinant inbred lines (RILs) generated from a cross between crop and wild sunflowers to assess selection on domestication traits and quantitative trait loci (QTL) in two contrasting environments, in Indiana and Nebraska, USA. Only a small fraction of plants (9%) produced seed in Nebraska, due to adverse weather conditions, while the majority of plants (79%) in Indiana reproduced. Phenotypic selection analysis found that a mixture of crop and wild traits were favoured in Indiana (i.e. had significant selection gradients), including larger leaves, increased floral longevity, larger disk diameter, reduced ray flower size and smaller achene (seed) mass. Selection favouring early flowering was detected in Nebraska. QTLs for fitness were found at the end of linkage groups six (LG6) and nine (LG9) in both field sites, each explaining 11-12% of the total variation. Crop alleles were favoured on LG9, but wild alleles were favoured on LG6. QTLs for numerous domestication traits overlapped with the fitness QTLs, including flowering date, achene mass, head number, and disk diameter. It remains to be seen if these QTL clusters are the product of multiple linked genes, or individual genes with pleiotropic effects. These results indicate that crop trait values and alleles may sometimes be favoured in a noncrop environment and across broad geographical regions.
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Affiliation(s)
- Eric J Baack
- Department of Botany, University of British Columbia, 6270 W University Blvd, Vancouver, BC, Canada V6T 1Z4.
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Warwick SI, Légère A, Simard MJ, James T. Do escaped transgenes persist in nature? The case of an herbicide resistance transgene in a weedy Brassica rapa population. Mol Ecol 2007; 17:1387-95. [PMID: 17971090 DOI: 10.1111/j.1365-294x.2007.03567.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The existence of transgenic hybrids resulting from transgene escape from genetically modified (GM) crops to wild or weedy relatives is well documented but the fate of the transgene over time in recipient wild species populations is still relatively unknown. This is the first report of the persistence and apparent introgression, i.e. stable incorporation of genes from one differentiated gene pool into another, of an herbicide resistance transgene from Brassica napus into the gene pool of its weedy relative, Brassica rapa, monitored under natural commercial field conditions. Hybridization between glyphosate-resistant [herbicide resistance (HR)]B. napus and B. rapa was first observed at two Québec sites, Ste Agathe and St Henri, in 2001. B. rapa populations at these two locations were monitored in 2002, 2003 and 2005 for the presence of hybrids and transgene persistence. Hybrid numbers decreased over the 3-year period, from 85 out of approximately 200 plants surveyed in 2002 to only five out of 200 plants in 2005 (St Henri site). Most hybrids had the HR trait, reduced male fertility, intermediate genome structure, and presence of both species-specific amplified fragment length polymorphism markers. Both F(1) and backcross hybrid generations were detected. One introgressed individual, i.e. with the HR trait and diploid ploidy level of B. rapa, was observed in 2005. The latter had reduced pollen viability but produced approximately 480 seeds. Forty-eight of the 50 progeny grown from this plant were diploid with high pollen viability and 22 had the transgene (1:1 segregation). These observations confirm the persistence of the HR trait over time. Persistence occurred over a 6-year period, in the absence of herbicide selection pressure (with the exception of possible exposure to glyphosate in 2002), and in spite of the fitness cost associated with hybridization.
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Affiliation(s)
- S I Warwick
- Agriculture and Agri-Food Canada, Eastern Cereal and Oilseeds Research Center, Central Experimental Farm, Ottawa, ON, Canada K1A OC6.
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